Precision unit conversion
Gold, silver and platinum aren't weighed in standard (avoirdupois) ounces — they use the older troy system, which is where a lot of confusion comes from when people compare a spot gold price to a kitchen scale reading.
The troy ounce is heavier than the ounce you'd use to weigh food: 31.1035 grams versus 28.3495 grams for a standard (avoirdupois) ounce — a difference of about 10%. This matters directly for anyone pricing bullion, jewellery or scrap gold, since precious metal spot prices are almost always quoted per troy ounce.
| Convert | Result |
|---|---|
| 1 troy ounce | 31.1035 g (1.09714 standard oz) |
| 1 troy pound | 373.242 g (12 troy oz) |
| 1 pennyweight (dwt) | 1.55517 g (1/20 troy oz) |
| 1 grain | 0.0647989 g |
| 1 gram | 0.0321507 troy oz |
| 1 standard ounce | 0.911458 troy oz |
The pennyweight (dwt) is still commonly used by jewellers, especially for weighing gold scrap and small items, since it's a more workable unit than a full troy ounce for smaller pieces.
The full converter moves between troy ounces, troy pounds, pennyweight, grains, grams, kilograms and standard ounces — useful for pricing bullion, scrap gold and jewellery.
Open Precious Metals converter →A troy ounce (used for gold, silver and other precious metals) is 31.1g, while a standard avoirdupois ounce is 28.35g — troy ounces are about 10% heavier.
One troy ounce is 31.1035 grams.
A pennyweight (dwt) is 1/20 of a troy ounce, or about 1.555 grams — it's a traditional unit still used by jewellers for weighing gold.
The troy system has been the standard for weighing precious metals since medieval times and was never replaced, so bullion markets, refiners and jewellers worldwide still quote weights and spot prices in troy ounces rather than switching to the avoirdupois ounce used for everyday goods.